Decals have been used for many years as one of the main forms of portraying graphics on truck bodies and truck trailers used in the trucking market. Large sums of money are spent each year in the application of signs, including decals, as a means of identification and advertising on truck bodies and trailers which travel the nation's highways each day.
Such decals historically have been designed to adapt to each different truck or trailer surface. For example, a standard undistorted decal can be applied, with satisfactory results, simply by affixing the same to the outer wall surface of a fiberglass trailer (FRP) which has a smooth, relatively flat skin, and to the outer wall surface of trailers having corrugated outer surfaces formed by horizontal indentations on the sub-straight. But undistorted decals affixed to the outer surfaces of exterior post trailers (which have vertical reinforcing posts or ribs secured to the outer surface of the trailer side walls) are distorted by the uneven surface to such an extent, and in such a way, as to result in an unacceptable final appearance. Therefore, decals for application to exterior post trailers have in the past been deliberately distorted as originally prepared in such a way as to compensate for the distortion that occurs in applying the flat sheet decal to the uneven, "waved" surface of the ribbed trailer wall. Application of a distorted decal to such a wall can result in an undistorted looking sign after application if the sign before application is prepared with a built-in distortion that will compensate for, or counteract, the distortion that results from application to the uneven surface. As an alternative, an undistorted sign could be pre-cut into pieces, or sections, using expensive die cutting equipment at the point of sign manufacture, each of the pre-cut pieces being separately installed, piece by piece, on the trailer wall surface in such a way as to provide an installed sign relatively free of distortion.
However, both of these prior attempts to solve the problem of installing decal signs on the side walls of vertically ribbed trailers were expensive in that they required much time and labor in preparation of the decal and/or in its installation. According to the present invention, a new method has been discovered for installing quickly and with a minimum amount of labor, undistorted decals which can be prepared at minimum cost, and which after installation, according to the invention, will remain substantially free of distortion in the final appearance.